IT is pretty broad, you can almost work for any large company, right? NJ is home to the North American headquarters of many pharmaceutical brands like Pzifer, Merk, Johnson & Johnson, etc. Most of those can be found in Somerset County along with telecommunications giants like Verizon Wireless, Att Wireless, Avaya, Bell Laboratories. Also, there are many Electronic Brands Headquarters in NJ like Sharp and LG not to mention many car brands like Mercedes-Benz, BMW, Jaguar-Land Rover, Ferrari-Maserati, all of which are the North American Headquarters. Tumi Luggage, Bed Bath & Beyond, Benjamin Moore Paint, all headquartered in NJ. Point is, if you have experience, a good resume, and know how you shouldn't find it too hard securing a position in one of these companies all of which have marketing and IT departments. Plus the list goes on and on of world class companies which are anchored and operate in NJ. Geese and everyone thinks the good jobs are only in NYC!
Anyway, why not go onto wikipedia and do a "companies based in NJ" you can see the list by county or even by city. Look what I found for Princeton (which is Mercer County)
Category:Companies based in Princeton, New Jersey - Wikipedia, the free encyclopedia
PS. I just took a look at that list myself and apparently there are a bunch of great companies already in Princeton like Berlitz, Dataram, Pharmasset etc. Good Luck with your job search. Also, NYC is always a great place to find a professional job obviously however, if you are going to live in NJ I wouldn't recommend commuting to NYC unless you are earning big bucks. I commuted for 4 years from Bergen County to Manhattan for college 5 days a week and I'm not gonna lie it was HELLISH!